diff --git a/authentik/stages/prompt/stage.py b/authentik/stages/prompt/stage.py
index 4bdf21c2d..5a84c0996 100644
--- a/authentik/stages/prompt/stage.py
+++ b/authentik/stages/prompt/stage.py
@@ -35,7 +35,7 @@ class StagePromptSerializer(PassiveSerializer):
     required = BooleanField()
     placeholder = CharField(allow_blank=True)
     order = IntegerField()
-    sub_text = CharField()
+    sub_text = CharField(allow_blank=True)
 
 
 class PromptChallenge(Challenge):